Long Questions: Sorting Materials into Groups | NCERT Summary: UPSC PDF Download

Q1: Explain in detail what are carbohydrates?
Ans: Carbohydrates are sugar molecules made up of carbon, hydrogen and oxygen. carbohydrates are one of the main nutrients found in foods and drinks. They are a rich source of energy. Our body breaks down carbohydrates into glucose. There are two main types of carbohydrates i.e sugar and starch. Carbohydrates help to fuel the central nervous system and it provides energy for working muscles. Lack of energy and stamina are the two main symptoms associated with a deficiency of carbohydrates. The food rich in carbohydrates are potatoes, beans, yoghurt, oats etc.

Q2: Explain in detail about proteins?
Ans: Proteins are highly complex substances that are present in all living organisms. Proteins are of great nutritional value and are directly involved in the chemical processes essential for life. They are an important component of food. They are needed for body growth and repair. Amino acids joined to form proteins. Proteins in the diet cause weakening of muscles. The deficiency of proteins leads to kwashiorkor and marasmus. The food rich in proteins is chicken, fish, milk, cheese etc.

Q3: Name any 3 vitamins, their sources and deficiency diseases caused by them?
Ans: The three vitamins are:

• Vitamin C: It is a water-soluble vitamin. It is needed for normal growth and development. Deficiency of vitamin C can cause scurvy, a disease that is characterised by bleeding gums, skin spots and swelling in joints. Foods rich in vitamin C sources are broccoli, potatoes, Citrus fruits, etc.
• Vitamin K: It is a group of fat-soluble compounds Vitamin K is important for blood coagulation. The deficiency of vitamin K can cause osteoporosis and leads to excessive bleeding. Foods rich in vitamin K sources are spinach, cereal grains, broccoli, etc.
• Vitamin A: It is a fat-soluble vitamin. It is important for normal vision, growth and a healthy immune system. The deficiency of vitamin A can cause night blindness and infertility. Foods rich in vitamin A sources are carrot, milk, fish, etc.

Q4: What do you understand by the term 'transparency'? Classify the following materials as transparent, translucent, or opaque: wax paper, glass, aluminum foil, clear plastic, and cardboard.
Ans: Transparency is the property of a material that allows light to pass through it. If a material allows light to pass through it such that objects can be clearly seen, it is called transparent. If the material only allows some light to pass through and objects cannot be clearly seen, it is called translucent. If no light can pass through the material, it is called opaque.

• Wax paper: Translucent (allows some light to pass through, but not clearly)
• Glass: Transparent (allows light to pass through clearly)
• Aluminum foil: Opaque (does not allow light to pass through)
• Clear Plastic: Transparent (allows light to pass through clearly)
• Cardboard: Opaque (does not allow light to pass through)

Q5: Explain the process of sorting materials into groups based on their properties.
Ans: Sorting materials into groups is done based on their properties such as color, shape, size, hardness, solubility, transparency, weight etc. For example, in a mixture of sand and water, sand is insoluble and settles at the bottom, whereas water is soluble. Similarly, materials can be sorted based on their hardness. Diamonds are the hardest substance, while talc is very soft. Thus, by understanding the properties of materials, we can sort them into different groups.

Q6: Why is it important to sort materials into groups? Give at least three reasons.
Ans: Sorting materials into groups is important for the following reasons:

• It helps to organize materials in a systematic way making it easier to study their properties.
• It aids in identifying the materials easily.
• It helps to decide the method of separation when more than one type of material is mixed together.

Q7: What is the difference between a lump of cotton wool and a lump of iron? List at least three differences based on their properties.
Ans: The differences between a lump of cotton wool and a lump of iron based on their properties are:

• Weight: Iron is much heavier than cotton wool.
• Hardness: Iron is hard, while cotton wool is soft.
• Magnetic properties: Iron is magnetic, meaning it is attracted to magnets, while cotton wool is not.
• Transparency: Iron is opaque (does not allow light to pass through), while cotton wool is translucent (allows some light to pass through).

Q8: What are the various properties based on which materials can be grouped?
Ans: Materials can be grouped based on various properties.
Some of these properties are:

• Color: Materials having the same color can be grouped together.
• Hardness: Materials can be grouped as hard or soft.
• Solubility: Materials can be grouped as soluble or insoluble in water.
• Weight: Materials can be grouped as heavy or light.
• Transparency: Materials can be grouped as transparent, translucent, or opaque.
• Shape and Size: Materials can be grouped based on their shape and size.

Q9: How is the property of solubility used in separating mixtures?
Ans: The property of solubility is used to separate mixtures by dissolving one component in a liquid while the other does not. For example, if you have a mixture of sand and salt, you can add water to it. The salt will dissolve in the water, while the sand will not. The sand can then be separated by filtering the mixture. The salt can be recovered by evaporating the water.

Q10: What is the importance of sorting materials into groups in scientific studies?
Ans: Sorting materials into groups is important in scientific studies because it helps in identifying and classifying different materials. By grouping similar materials together, scientists can better understand their properties and behavior, which can be useful in various scientific research and experiments. It also helps in making predictions about the properties of new materials. Moreover, it simplifies the study of materials by reducing the complexity of dealing with numerous individual materials.